Teenagers have the most climate-warming diets of any age group globally, according to a major international study analyzing dietary patterns across 149 countries over two decades. Researchers found that adolescents and young adults generate the highest food-related greenhouse gas emissions per person, largely due to greater consumption of red meat, dairy products, and highly processed foods. The study, led by the University of Birmingham and published using global dietary data from 2000 to 2019, also reveals a surprising trend: while teenagers have the highest per-person dietary emissions, adults aged 60 and above are now the fastest-growing contributors to global food emissions because of ageing populations.

With food systems already responsible for around one-third of global greenhouse gas emissions, the findings suggest climate and nutrition policies must become more targeted, balancing environmental goals with public health and changing demographics.

Key Findings at a Glance

Global Study Analyzed Diets Across 149 Countries

The research tracked dietary habits across 22 age groups in 149 countries, making it one of the most comprehensive studies on food-related emissions by age.

• Researchers found that teenagers have the most climate-warming diets across almost every country examined.
• Their diets consistently contained higher quantities of red meat, dairy products, processed foods, sugary foods, and beverages.
• These foods have significantly larger carbon footprints because livestock farming, feed production, land-use change, and food processing generate substantial greenhouse gas emissions.
• In developing countries, rising incomes have further increased food consumption among younger populations, contributing to even higher dietary emissions.

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Why Red Meat Has the Largest Climate Impact

Among all food categories, red meat emerged as the single biggest contributor to dietary greenhouse gas emissions.

Cattle produce large amounts of methane, a greenhouse gas with a warming potential approximately 28 times greater than carbon dioxide over a 100-year period, according to the Intergovernmental Panel on Climate Change (IPCC).

Livestock farming also requires extensive grazing land, large quantities of water, and feed production, all of which increase environmental impacts.

The Food and Agriculture Organization (FAO) estimates that livestock supply chains account for approximately 14.5% of global human-induced greenhouse gas emissions, with beef production contributing the largest share.

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Older Adults Are Becoming the Fastest-Growing Source of Food Emissions

Although teenagers have the most climate-warming diets on an individual basis, the study highlights a different long-term trend.

• Between 2000 and 2019, global food-related emissions increased by approximately 2.1 billion tonnes of CO₂ equivalent.
• People aged 60 years and above contributed nearly one-quarter of this increase.

The reason is not that older adults consume more carbon-intensive diets. Instead, global populations are ageing rapidly.

• Countries including the United States, Japan, and Western European nations now have significantly larger elderly populations, meaning total dietary emissions continue rising simply because more older adults require food.

Professor Yuli Shan, one of the study’s corresponding authors, noted that the findings challenge the common assumption that younger consumers are solely responsible for rising dietary emissions.

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Population Ageing Is Reshaping Climate Policy

The research demonstrates an important distinction between per-person emissions and total emissions.

Teenagers generally consume diets with higher emissions per individual, while older adults collectively contribute more because their population continues to grow.

This demographic shift means governments must rethink food-related climate strategies.

Rather than applying universal dietary recommendations, researchers suggest tailoring policies to different age groups and regional conditions.

Also Read: What Is Sustainable: Meat-Based Diet Or Plant-Based Diet?

Nutrition and Climate Goals Must Be Balanced

The study also highlights an important challenge for developing countries.

In many low- and middle-income nations, increased meat, dairy, and egg consumption has improved nutrition and reduced undernourishment.

Professor Klaus Hubacek from the University of Groningen emphasised that improving diets in poorer countries often leads to higher emissions, creating difficult trade-offs between nutrition and climate objectives.

This means reducing emissions cannot come at the expense of food security or public health.

Instead, experts recommend encouraging sustainable protein sources, improving agricultural efficiency, reducing food waste, and promoting balanced diets.

Also Read: Global Model Reveals How Diet Changes Can Lower Environmental Impact

Different Age Groups Need Different Solutions

Researchers argue that future climate policies should focus on age-specific interventions.

• For younger populations, schools, universities, and food retailers can promote healthier, lower-carbon meal options.
• For ageing populations, governments should ensure nutritious diets while encouraging foods with lower environmental impacts.

The study also aligns with separate research showing that young, urban, well-educated men often have the largest dietary carbon footprints, reinforcing the need for targeted rather than universal climate policies.

According to first author Yanxian Li, policymakers must rethink climate responsibility to avoid overlooking demographic changes that increasingly shape food emissions.

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Why These Findings Matter

The findings show that teenagers have the most climate-warming diets, but demographic change is shifting where future food emissions originate. As populations continue to age and incomes rise worldwide, governments will need smarter food policies that consider age, nutrition, and regional economic conditions. Encouraging healthier diets, reducing reliance on carbon-intensive foods, investing in sustainable agriculture, and expanding access to climate-friendly protein alternatives can help lower emissions without compromising nutritional needs.

Understanding who contributes most to food-related emissions is an important step toward designing more effective and equitable climate strategies.

Also Read: Can Lab-Grown Meat Revolutionize Sustainable Eating And Farming?

Frequently Asked Questions

1. Why do teenagers have the highest dietary carbon footprint?

Teenagers generally consume larger amounts of red meat, dairy products, processed foods, and sugary beverages, all of which have higher greenhouse gas emissions than most plant-based foods.

2. Which institution led the study?

The research was led by the University of Birmingham in collaboration with international researchers.

3. How many countries were included in the study?

The researchers analysed dietary data from 149 countries covering 22 age groups between 2000 and 2019.

4. Why are older adults becoming a larger source of food emissions?

The increase is mainly due to population ageing. More people are living longer, so total dietary emissions rise even if individual diets remain relatively unchanged.

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